Look in your owners manual or the recommended maintenance manual that came with the vehicle. Look for the timing belt maintenance and if it says to replace the belt at a certain interval, then replace it. If it says to inspect it, then its probably a non interference engine. If its not listed, then you may have a timing chain instead.
BTW, I do not have experience with this particular vehicle, however, if it was an interference engine, they usually recommend replacement of the belt at certain intervals, not just inspect. In addition, Toyota had switched most of its engines to chains by 2006, but your dealer should know that.